Humalog U-200 KwikPen holds twice as many units of insulin (600 units vs. 300 units) as the U-100 formulation in the same three-milliliter cartridge. This offers patients a pen that lasts longer between pen changes, allowing for fewer changes every month.* Humalog U-200 KwikPen delivers the same dose in half the volume of Humalog U-100 KwikPen with no dose conversions required, and can be dialed in one-unit increments to a maximum of 60 units per injection.